What is a normal battery health for iPhone 13 pro

Yours is normal.

See this excerpt from the "Your battery's maximum capacity" section of the support article: iPhone Battery and Performance - Apple Support

"A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge." In other words, if maximum capacity is below 80%, the battery is below normal performance. You can still use a device with a lower health percentage than 80% but for optimal usage you may wish to consider having it changed when it reaches 80%.

Batteries are consumables and 1-2% loss per month is perfectly normal. According to iPhone Battery and Performance - Apple Support , Apple apparently only considers it unusual (and warrant-able) if a battery drops below 80% maximum capacity in less than a year after you receive it. Ergo, some storage loss as you use it is expected and acceptable. Incidentally, that possible 20% drop over the first 12 months equates to 1-2% drop per month being within the range of what Apple finds acceptable.

As for the battery running out faster, newer operating system versions may add more features putting a drain on batteries. Check the Battery Health feature and see which apps are using the most power. Decide if you can live without them, or at least have it so they are not using power in the background when you aren't actively using them.